From fill-in receptionist to the top of her creative game at Leo Burnett

When Esurance passed on this month's Super Bowl and ran a commercial in the first post-game break, it offered the $1.5 million it saved on the less expensive ad through a Twitter contest.

Five million tweets and one lucky winner later, the social media stunt was the unofficial Big Idea of this year's Big Game. Score another win against the odds for Susan Credle, chief creative officer of Chicago ad agency Leo Burnett, which directed the campaign.

Credle, a driven and diminutive Southerner, has a long history of developing big ideas, from an iconic ensemble of anthropomorphized M&M's to tuxedoed thespians dramatically trading text messages onstage. But it is the creative arc of her own back story that is perhaps most remarkable: She was a fill-in receptionist who has become one of the most influential women in advertising during a prolific three-decade career.

If dashing 1950s-era Leo Burnett creative head Draper Daniels is the acknowledged inspiration for Don Draper on television's "Mad Men," then Credle is a real-life Peggy Olson. Credle spent 24 years at BBDO in New York, starting at the absolute bottom.

"They said we'll pay you $11,500 to fill in for the receptionists when they need to go to the bathroom," Credle said. "That was my job."

She worked her way up to creative director at BBDO through seized opportunities, long hours and missed vacations. Along the way, she developed the wildly popular M&M's characters, helped turn Cingular Wireless into a household name and created award-winning work for clients such as FedEx, Pizza Hut and Pepsi.

Since arriving at Leo Burnett more than four years ago, she has raised the bar for the creative department, fomenting a collaborative environment and producing some of the venerable agency's most memorable campaigns in decades: the home of the Marlboro Man begot Allstate Insurance's "Mayhem" under Credle.

"She's really changed this place," said Charley Wickman, 51, executive creative director for Allstate and a 20-year veteran at Leo Burnett. "I think this place has a swagger that it never had in the other years that I was here."

For Credle, 50, the journey to Chicago and the top of her profession started in North Carolina, went through New York and owes much to not going on a trip to Europe after college.

Credle was born in Chapel Hill, where her father was attending medical school at the University of North Carolina and her mother was a high school teacher. Her parents divorced in 1971, and she and her brother moved with their mother to Greenville, S.C., shuttling between states through high school.

She attended college at the University of North Carolina, majoring in journalism, where the seeds for a career in advertising were planted. Credle also cheered on classmate and future NBA superstar Michael Jordan.

After graduating in 1985, Credle wanted to take a trip to Europe. Her father was not supportive of the idea, and she settled instead for a summer in New York.

"A lot of my friends were going to Europe for the summer to see all the countries, and I didn't have any money," Credle said. "So I decided, maybe I should move to New York for three months, and that will be my European tour."

Credle and her college roommate, Kinsey Ferguson, booked $29 one-way tickets from North Carolina on the now-defunct People Express Airlines, landing in New York with some pocket change and arrangements for a subleased studio on 63rd Street near Park Avenue on the tony Upper East Side.

Hoping to find a job in advertising, Credle loaded up on trade publications to look for leads, based on the advice of a college professor. That year, New York-based BBDO was named agency of the year by Advertising Age, inspiring Credle to knock on its door. She got the receptionist job.

The roommates supplemented their income as coat check girls at The Post House, an upscale restaurant across from their apartment. The gig included free meals and a chance to rub elbows with Manhattan's elite.

"It was a very fine restaurant, and there were a lot of wealthy patrons, and so while the patrons were dining, we would occasionally try on the fur coats and believed that we too one day would be wearing fur coats," said Ferguson, 51, now an apparel executive living in Connecticut.

Determined to stay in New York when the summer and sublease ran out, the women found another studio in a somewhat grittier neighborhood.

"We moved the majority of our worldly possessions in a grocery cart," Ferguson said. "I distinctly recall rolling the vacuum cleaner down Park Avenue over to 78th Street."

Ready to move up, Credle taught herself to type and landed a job as a secretary. She was able to station herself in the creative department near a cluster of art directors, figuring she could offer to help them write stuff and work her way onto the team.